E-gad, he’s making another one of those crazy pop-up things

[Craig DeShong]

Thanks for stopping by.

I’ve been working toward finishing the clutch.  This post starts with cutting the gear teeth.  This is a 42 tooth gear with a diametral pitch of 14, so the teeth are quite large, at least for the gears I’ve made in the past.  With a whole depth approaching 5/32 inch the going was slow. It took over three hours  to cut these teeth but I’m happy with the result.



Below is a view of the finished gear.


Next up was the rotor.  This is the round piece in the center of the clutch, affixed to the main shaft with a woodruff key.  I didn’t work toward smoothing the face of the rotor beyond what finish the lathe gave me.  It probably benefits from a bit of a rough finish so it can grab the rollers in the clutch body.


Speaking of the rollers, here is a view of the clutch just prior to final assembly.  The brass cylinders are the rollers and they are trapped between the rotor and the “ramps” in the clutch body, thus locking the clutch in the forward direction.


Nothing like a test to make sure the clutch works as designed.  It spins very freely in the reverse direction and locks positively in the forward direction.  I couldn’t be more pleased.
<a href="https://www.youtube.com/watch?v=Yv-C1dkZy-Q" target="_blank">http://www.youtube.com/watch?v=Yv-C1dkZy-Q</a>

To finish the clutch I need to make the bearing covers.  These help block out any dirt that might find it’s way into the clutch and they will also hide the ball bearings from view.  I wouldn’t want any “purists” to come by, observe the finished model, and exclaim, “sacrilege, Sacrilege, SACRILEGE; ball bearings on an Otto Langen Engine…. For all SHAME!!!!”.   

[Kim]

Craig, that is really slick!  Do all six of the rollers engage at the same time? or do a few of them do more work than the others?  Just curious.  It looks like it works really well! 

Kim

[Admiral_dk]

Very nice result with the clutch 

[Craig DeShong]

Thanks for stopping by, and thanks Kim & Per for your comments.

Kim:  Hard to say; I’d guess only one or two (the ones gravity locates at the bottom of the ramp) engage the clutch.  All probably get used one time or another because the clutch could be at any rotation when its motion is reversed.  The clutch seems to engage almost instintaniously, with no noticeable back rotation.  This is very desirable because any lost motion in this engine will result in noticeable loss in performance.  There just isn’t that much extra power available.

Today I didn’t get much done; just managed to finish up the clutch by making the two end covers. 


Here is a photo of the completed clutch, installed on the main shaft.

[Craig DeShong]

Thanks for stopping by.

Occasionally I try to take a short-cut; sometimes it works out, other times; not.  Usually it’s just laziness and I often pay the price for it.  You would think I might learn that haste makes waste.

That happened with the main shaft drive gear I was making.  I spent a whole day carving it from the blank, facing both sides and turning it to the correct diameter; then drilling, boring, and finally reaming the center hole for the shaft.

I then made an arbor which I used to mount it to the dividing head in order to cut the gear teeth.  After all that work you would think I would have cut a keyway into the arbor so that the gear could not turn on the arbor while I was forming the gear teeth; but I didn’t think it was necessary so I saved five minutes and proceeded to cut the gear teeth.

Needless to say, when I got all the way around the gear, it was obvious that the gear blank had rotated on the arbor and to save five minutes in not cutting a keyway, two entire days of work was wasted; plus the material was ruined; not to mention the unnecessary wear on an expensive gear cutter.

I repeated the same operations on the secondary shaft driven gear; this time  cutting a keyway in the arbor and using a woodruff key in the arbor to prevent the gear blank from rotating  and everything came out fine.

Here’s a photo of the arbor.



A photo of the secondary shaft gear blank with the gear teeth being cut.  This is a seventy tooth gear.



Finally a photo of the finished gear.

[fumopuc]

Craig, I enjoy it very much to follow your progress. The clutch is splendid.

[Craig DeShong]

Thanks for your thoughtful comment Achim; thanks also for those just stopping by to see the progress.

While I’m waiting for my replacement gear blank I thought I’d start on the piston and ring.  I spent the whole day on the piston and I’m happy with the result.

Below is a photo I took once I faced the material and turned it to the correct diameter.  In this photo I’m cutting the ring grove.  I have this fine grooving tool that I rarely use but it is just the ticket when I need it.


With the ring grove established, I’ve turned the part around in the lathe and faced it to the correct piston height.  Here I’m boring out the skirt.



The piston is connected to the rack by a bracket that threads into the piston.  Here I’m threading the piston to accept the bracket.  I’ve also cut a relief into the face of the piston to accept a locking nut.



A view of the finished piston.


I’m thinking I might have a ring blank left over from the 3rd generation Otto Langen model I finished last Fall; I’ll need to check.  If so that should make the finishing of the ring blank pretty quick.  Since the bore of this engine matches the 3rd generation I just built I can use the same ring turning fixtures so I don’t need to make new ones.

[Craig DeShong]

Thanks for stopping by.

The majority of work today focused on the single piston ring used by this model.  I was correct in thinking I had a spare blank left over from when I made the 3rd gen Otto Langen; this saved me the trouble of cutting one from a cast iron blank.
Here I’m placing the blank on my fixture to turn the outside diameter.  I’ve collapsed it with a radiator clamp and then am using the front “washer-clamp” to hold it in place on the fixture in its compressed form.


Below is a view of the ring, once I’ve turned it to its outside diameter of 2 inches.  It’s sitting on the fixture just prior to removal with the front “clamp” removed.


Onto the surfacing machine to get it down to its correct width.
 

Here I’ve slipped it into the fixture I’ll use to turn the inside diameter.  I’ve placed it in the fixture but have as yet to apply the outside clamp to secure it in place.



The finished ring.  These Otto Langen rings are unique in that the ring gap is cut on a diagonal and the ring is somewhat thinner than a “normal” ring.  The ring needs to be thin enough so that the piston will fall to the bottom of the cylinder with just the weight of the piston and rack.  Placing this piston and ring assembly in the cylinder they don’t quite slide to the bottom with the weight of the piston alone in a dry cylinder.  I’m thinking (hoping) that with a bit of oil and the weight of the rack I’ll be ok.



The last item today was fabrication of the bracket that attaches the rack to the piston.

[Craig DeShong]

Thanks for stopping by.  Yesterday I worked on the cylinder head, today I started on the rack.

Below is a photo of the cylinder head; in progress.


I failed to take any photos while I made this cylinder head; here is a final photo of it installed on the cylinder, complete with spark plug.


Once the head was complete I started on the rack.   I remember reading a discussion by Wayne Grenning when he made his full size Otto Langen.  Due to cost of material, no doubt; he made the rack as one piece and the lift flange as another, then solver soldered them together.  One of the benefit of modeling is that often the cost of one part verses two parts is miniscule.  I chose to make the rack and lift flange as one piece.  Here I’m just beginning the work this piece of hot rolled A36 down to the correct size.  I’m using hot rolled steel (as opposed to cold rolled) because the stresses in cold rolled steel would warp the piece as cut the gear teeth.  My mill table had just enough travel to make this cut in one pass.



With one straignt edge established It was time  to work this piece of steel down to it’s final width.


Here I’m working the opposite ege down to the final 5/8th inch. The larger vertical part will become the lift flange for the rack/piston as well as the trip for the rack/pawl.


The Rack, still needing it’s gear teeth cut.  I’m leaving the lift flange in rough oversize for now.  Once I get the engine together I’’ll be able to see what the exact measurements of the flange should be.  I’ve left a generous amount of material so I should have enough.

[Johnmcc69]

 
 

 John

[Roger B]

Excellent      That rotary milling head is a wonderful tool 

[Craig DeShong]

Thanks for stopping by.  Also, thanks to John and Roger for your comments. 

Roger, yep… if it broke I’m go out and get another tomorrow!!!

It’s been a while since I last posted, and it’s been a while since I’ve been in the shop.  “life” has been getting in the way of my model making, but as I told Brian a while back… if I’m out of the shop for a while, when I go back I’ll find that no one has completed my model for me.   Still lots of fun patiently awaits.

Just in the last few days I’ve gotten back to work and I’m continuing on making the rack.  Before I can cut the teeth in the rack I need to make some tooling.  This will be a bar on which I’ll attach the involute gear cutter and when mounted in the lathe will allow me to progress down the length of the rack, cutting teeth as I go.

The tooling has a shoulder to hold the gear cutter and a "nut" (a rather long nut) is threaded up against the gear cutter, holding it in place.  If I make the “nut” first, then when I cut the threads in the bar I can keep trying the “nut” till it threads on nicely. In the photo below I’ve cut the “nut” to length and then I’ve drilled and bored it out to the correct ID.


Now I’m cutting the internal threads in the “nut”.


With the “nut” complete, I’ve started on the bar.  Here I’ve cut the diameter down on the one side so the gear cutter will slide up into position and I've staged the area which I will thread for the "nut".


Here I’m cutting the threads on the bar.


With my tooling complete I can now begin cutting the teeth in the rack.


Here is a better close up of the setup.


And here I’ve just completed the first few teeth.  This is slow going; it takes a few minutes to cut each tooth.

[Craig DeShong]

Thanks for stopping by.  I spent a few hours in the shop today, working my way down the piece of steel that will become the rack for this model.  Just a few photos of the progress.  I still have around two dozen or so teeth to cut before I can call this task complete.

[scc]

Nice!   Loads of concentration required I imagine!     Terry

[crueby]

Very nice!  Is each tooth cut in one pass? Or are there multiple passes to reach the depth?